Super Le Tour Frameset Not Mitered
 

Had the opportunity to look inside a Super Le Tour frame from around 1985 and was surprised to see the tube ends are square cut and squashed at the head tube junction and seat tube/down tube junction to make room for the opposing tube to butt up to it. The head tube+lugs are one piece so it was wide open where the top tube and down tube joined in to the head tube. Might be a Panasonic frame, but was surprised they took this type of a shortcut in production.

Are you sure it was Panasonic and not Greenville?

This is definitely not a Panasonic built Le Tour, in 1985, they were built at Schwinn's Greenville, MS factory.

Ir could just as easily have been be a M-a-t-s-u-s-h-i-t-a or Bridgestone manufactured frame, as Greenville. It would come down to whether Schwinn was willing to pay their contractors for the mitering operation. I've seen a lot of big name Reynolds 531DB frames with non-mitered tubes. .

FWIW, Nikko one-piece, bulge-formed headtube/head lug frame fittings were pretty widely used on mid-level Japanese frames.

By no means as crude as the OP's description, but even some Paramounts went cheap with the mitering. Note the straight-cut seatpost mitered only to the downtube and not the BB.

https://cimg8.ibsrv.net/gimg/bikefor...b97143d620.jpg

It's the legacy built around the frame - not the frame itself - that gives a particular bike status in the popular pecking order of vaulted marquees.

-Kurt